/Engine/Plugins/Experimental/PlanarCutPlugin/Source/PlanarCut/Public/PlanarCut.h
int32 AddPlane ( const FPlane & P, int32 CellIdxBehind, int32 CellIdxInFront, const [TArray](API\Runtime\Core\Containers\TArray)< int32 > & PlaneBoundary )